In recent years, in a color multi function peripheral (hereinafter abbreviated to an MFP) incorporating integrally with a copying machine and a printer or additionally a facsimile function and sharing a developed image forming portion, an image forming apparatus integrally incorporating a scanner for irradiating light to a document on a document table, detecting optical image information reflected from the document, and reading a document image in a housing has been widely used. In the scanner for detecting reflected light from a document on the document table and reading a document image, to prevent a reduction in the reading accuracy, it is necessary to prevent the scanner from transfer of external vibration. Conventionally, as disclosed in Japanese Patent Application Publication 11-355479, as a countermeasure for preventing a scanner from transfer of vibration, there is an apparatus for supporting the scanner using vibration-proof rubber.
In the apparatus disclosed in Japanese Patent Application Publication 11-355479, a support frame of an image reading apparatus for storing a line CCD is attached to a housing using a vibration-proof member having a vibration-proof rubber body to prevent transfer of vibration from a floor.
However, the rubber series vibration-proof member of the apparatus disclosed in Japanese Patent Application Publication 11-355479 Publication is for preventing vibration from a floor of an installation place due to walking or vibration due to an operation of the image reading apparatus itself from transfer to the support frame and does not prevent the scanner integrally incorporated in the housing of the image forming apparatus having a image forming portion and a printer portion from transfer of a vibration or a shock generated in the image forming portion or the printer portion. Therefore, in recent years, an apparatus that between the periphery of the scanner and the housing of the image forming apparatus for supporting the scanner, for example, a gelatinous cushioning member is installed to prevent a vibration or a shock generated in the image forming portion or printer portion from transfer to the scanner is in the development stage.
On the other hand, there are some scanners which can optionally select either of a document cover for covering a document table and an automatic document feeder for supplying a document to the document table. However, when a scanner which can optionally select either of the document cover and the automatic document feeder is incorporated integrally in the image forming apparatus, depending on a difference in the weight applied to the scanner, the distortion amount of a cushioning member for supporting the scanner differs.
Therefore, when the standard of the cushioning force of the cushioning member is adjusted to the document cover, if the automatic document feeder is exchanged with a heavy automatic document feeder, the distortion amount of the cushioning member is increased. As a result, the scanner extremely goes down in the housing of the image forming apparatus, thus the bottom of the scanner makes contact with the housing of the image forming apparatus, and there is the possibility that vibration may be transferred to the scanner, and furthermore, the level difference between the document table on the top of the scanner and the top of the housing is increased, and there is the possibility that the document feed may be impeded.
On the other hand, when the standard of the cushioning force of the cushioning member is adjusted to the automatic document feeder, if the document cover is exchanged with a light document cover, the scanner little goes down in the housing, thus the level difference between the document table on the top of the scanner and the top of the housing cannot be kept at an appropriate amount, and there is the possibility that vibration may be transferred from the top side of the housing to the scanner.